xref: /openbmc/linux/arch/mips/math-emu/dp_fsp.c (revision 8fdff1dc)
1 /* IEEE754 floating point arithmetic
2  * double precision: common utilities
3  */
4 /*
5  * MIPS floating point support
6  * Copyright (C) 1994-2000 Algorithmics Ltd.
7  *
8  * ########################################################################
9  *
10  *  This program is free software; you can distribute it and/or modify it
11  *  under the terms of the GNU General Public License (Version 2) as
12  *  published by the Free Software Foundation.
13  *
14  *  This program is distributed in the hope it will be useful, but WITHOUT
15  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
17  *  for more details.
18  *
19  *  You should have received a copy of the GNU General Public License along
20  *  with this program; if not, write to the Free Software Foundation, Inc.,
21  *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
22  *
23  * ########################################################################
24  */
25 
26 
27 #include "ieee754dp.h"
28 
29 ieee754dp ieee754dp_fsp(ieee754sp x)
30 {
31 	COMPXSP;
32 
33 	EXPLODEXSP;
34 
35 	CLEARCX;
36 
37 	FLUSHXSP;
38 
39 	switch (xc) {
40 	case IEEE754_CLASS_SNAN:
41 		SETCX(IEEE754_INVALID_OPERATION);
42 		return ieee754dp_nanxcpt(ieee754dp_indef(), "fsp");
43 	case IEEE754_CLASS_QNAN:
44 		return ieee754dp_nanxcpt(builddp(xs,
45 						 DP_EMAX + 1 + DP_EBIAS,
46 						 ((u64) xm
47 						  << (DP_MBITS -
48 						      SP_MBITS))), "fsp",
49 					 x);
50 	case IEEE754_CLASS_INF:
51 		return ieee754dp_inf(xs);
52 	case IEEE754_CLASS_ZERO:
53 		return ieee754dp_zero(xs);
54 	case IEEE754_CLASS_DNORM:
55 		/* normalize */
56 		while ((xm >> SP_MBITS) == 0) {
57 			xm <<= 1;
58 			xe--;
59 		}
60 		break;
61 	case IEEE754_CLASS_NORM:
62 		break;
63 	}
64 
65 	/* CAN'T possibly overflow,underflow, or need rounding
66 	 */
67 
68 	/* drop the hidden bit */
69 	xm &= ~SP_HIDDEN_BIT;
70 
71 	return builddp(xs, xe + DP_EBIAS,
72 		       (u64) xm << (DP_MBITS - SP_MBITS));
73 }
74